An open-end spinning device with an aerostatic axial bearing for a spinning rotor is known, for example, from the generic EP 0 435 016 B1. The aerostatic bearing described therein has a bearing plate with a bearing surface that works with the end of the rotor shaft by allowing the air to blow out through the bearing surface and into the air gap of the axial bearing. The bearing plate has one or more bore holes for letting the air out. The materials from the bearing plate and the shaft end form a low-friction material pairing. Before the air exits the air gap, it passes through a throttle device made from a porous material, such as sintered materials or carbon materials, to name a few.
The throttle devices for a generic axial bearing known from the state of art are made from an extruded semi-finished product made of carbon material. In this case, the raw material is extruded at a temperature of approx. 2,500° C. to 3,000° C. to obtain a cylinder-shaped semi-finished product. In a subsequent work process, individual disks are sliced from this semi-finished product for later use as throttle devices in the axial bearing.
To increase the loading capacity of the aerostatic axial bearing under continuous duty, DE 100 62 106 A1 suggests adjusting the air flowing through the throttle device with numerous microscopic holes. If one has many bore holes compared to one or few, the bore deviations should even themselves out mutually and this should maintain a more precise airflow. In this case, one should be able to adjust the volume of air current flowing through the throttle device by increasing or decreasing the number of microscopic holes.